After some update Firefox 65.0 does not play YouTube videos anymore in some virtual machines of Virtualbox 6.04. The following VM were tested and found wrong Xubuntu 18.04.2, Ubuntu Mate 18.04.2 both with Linux 4.18 and Ubuntu 16.04 with Linux 4.15. The same Firefox release does play those video correctly using real hardware with Ubuntu Mate 18.04.2 and Linux 4.15 and in the Virtual machines of Linux Mint 19.1 and Peppermint 9, both with Linux 4.15. Also the Firefox Development 66.0b7 edition has that same problem.
Opera, Chrome and Chromium still do play those videos correctly in the Virtual Machines, which do not play with Firefox.
On starting the YouTube video, it starts, it buffers to get the normal 2 minutes. But after a approx. 9 frames, it halts displaying the video.
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: firefox 65.0+build2-0ubuntu0.18.04.1
ProcVersionSignature: Ubuntu 4.18.0-15.16~18.04.1-generic 4.18.20
Uname: Linux 4.18.0-15-generic x86_64
AddonCompatCheckDisabled: False
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: bertadmin 1776 F.... pulseaudio
/dev/snd/pcmC0D0p: bertadmin 1776 F...m pulseaudio
/dev/snd/timer: bertadmin 1776 f.... pulseaudio
BuildID: 20190128144255
Channel: Unavailable
CurrentDesktop: MATE
Date: Fri Feb 15 10:55:10 2019
DefaultProfileExtensions: extensions.sqlite corrupt or missing
DefaultProfileIncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
DefaultProfileLocales: extensions.sqlite corrupt or missing
DefaultProfilePrefSources:
/usr/lib/firefox/defaults/pref/all-ubuntumate.js
prefs.js
DefaultProfileThemes: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
IfupdownConfig:
# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback
IpRoute:
default via 192.168.0.1 dev enp0s3 proto dhcp metric 100
169.254.0.0/16 dev enp0s3 scope link metric 1000
192.168.0.0/24 dev enp0s3 proto kernel scope link src 192.168.0.109 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown
Profile0Extensions: extensions.sqlite corrupt or missing
Profile0IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
Profile0Locales: extensions.sqlite corrupt or missing
Profile0PrefSources:
/usr/lib/firefox/defaults/pref/all-ubuntumate.js
prefs.js
Profile0Themes: extensions.sqlite corrupt or missing
Profiles:
Profile0 - LastVersion=66.0/20190211185957 (Out of date)
Profile1 (Default) - LastVersion=65.0/20190128144255 (In use)
RunningIncompatibleAddons: False
SourcePackage: firefox
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/01/2006
dmi.bios.vendor: innotek GmbH
dmi.bios.version: VirtualBox
dmi.board.name: VirtualBox
dmi.board.vendor: Oracle Corporation
dmi.board.version: 1.2
dmi.chassis.type: 1
dmi.chassis.vendor: Oracle Corporation
dmi.modalias: dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:rvnOracleCorporation:rnVirtualBox:rvr1.2:cvnOracleCorporation:ct1:cvr:
dmi.product.family: Virtual Machine
dmi.product.name: VirtualBox
dmi.product.version: 1.2
dmi.sys.vendor: innotek GmbH
Just found out, that you can make Firefox play that video by pressing 'Pause' and afterwards 'Play', when it halts. I think, it looks like a timing issue in Firefox itself. Still it is very confusing for a user and I had the same problem trying to play voice maWhatsapp